MCB 2010 COMPREHENSIVE EXAMS QUESTIONS
AND ANSWERS SURE A+
✔✔What is the main component of bacterial cell walls? - ✔✔peptidoglycan
✔✔Gram-positive - ✔✔thick layer of peptidoglycan, Appear purple
✔✔Gram-negative - ✔✔thin layer of peptidoglycan, appear pink
✔✔What molecule in gram-negative bacterial cell walls can cause fever, vasodilation,
inflammation, shock, and blood clotting in humans? - ✔✔LPS- lipopolysaccharide
✔✔The significance of the plasma membrane is that - ✔✔it selectively allows some
molecules to pass into the organism, it prevents movement of molecules out of the
organism, and it is the site of protein synthesis
✔✔Gram positive cells have... - ✔✔multiple layers of peptidoglycan that help retain the
crystal violet stain
✔✔the outer membrane of Gram negative cells is more permeable than the plasma
membrane because - ✔✔porin proteins establish holes in the outer membrane
✔✔Name the structure that some bacteria have that help them survive unfavorable
conditions? - ✔✔endospores
✔✔How do cell walls differ in bacteria and archaea? - ✔✔archaea don't have
peptidoglycan
✔✔What organisms have cell walls? - ✔✔archaea, bacteria, fungi, and algae
, ✔✔Eukaryote and prokaryote flagella have the same structure - ✔✔False (9 + 2
microtubules)
✔✔resolution - ✔✔ability to distinguish two points that are close together
✔✔contrast - ✔✔differences in intensity between two objects or an object and it's
background
✔✔The total magnification using a 10 ocular and a 100 objective would be - ✔✔1000
✔✔Dark field - ✔✔a bright specimen
✔✔Bright field - ✔✔colored or clear specimen
✔✔Phase-contrast - ✔✔specimen has light and dark areas
✔✔What part of the microscope do you change if you want to have less light entering
the condenser? - ✔✔diaphragm
✔✔What is the primary purpose to use a stain in microscopy? - ✔✔To enhance contrast
✔✔Why do you have to heat fix the smear on the slide when performing staining
techniques? - ✔✔kills bacteria, allows easy staining, firmly adheres the smear
✔✔Why are most bacterial stains basic stains? - ✔✔Because they only need to
determine size, shape, and arrangement of cells
✔✔Gram Stain Procedure - ✔✔
✔✔Why does the Gram stain not work well for Mycobacterium - ✔✔It has large amounts
of waxy lipids in their cell walls so they do not readily stain with the water-soluble dyes
✔✔Which stain would you use for Mycobacterium? - ✔✔Acid fast stain
✔✔What stain uses carbolfuchsin? - ✔✔Flagellar stain
✔✔A ________ is a substance that binds to a dye and makes it less soluble. -
✔✔mordant
✔✔Name 3 simple stains - ✔✔Crystal violet
Methylene blue
Gram safranin
AND ANSWERS SURE A+
✔✔What is the main component of bacterial cell walls? - ✔✔peptidoglycan
✔✔Gram-positive - ✔✔thick layer of peptidoglycan, Appear purple
✔✔Gram-negative - ✔✔thin layer of peptidoglycan, appear pink
✔✔What molecule in gram-negative bacterial cell walls can cause fever, vasodilation,
inflammation, shock, and blood clotting in humans? - ✔✔LPS- lipopolysaccharide
✔✔The significance of the plasma membrane is that - ✔✔it selectively allows some
molecules to pass into the organism, it prevents movement of molecules out of the
organism, and it is the site of protein synthesis
✔✔Gram positive cells have... - ✔✔multiple layers of peptidoglycan that help retain the
crystal violet stain
✔✔the outer membrane of Gram negative cells is more permeable than the plasma
membrane because - ✔✔porin proteins establish holes in the outer membrane
✔✔Name the structure that some bacteria have that help them survive unfavorable
conditions? - ✔✔endospores
✔✔How do cell walls differ in bacteria and archaea? - ✔✔archaea don't have
peptidoglycan
✔✔What organisms have cell walls? - ✔✔archaea, bacteria, fungi, and algae
, ✔✔Eukaryote and prokaryote flagella have the same structure - ✔✔False (9 + 2
microtubules)
✔✔resolution - ✔✔ability to distinguish two points that are close together
✔✔contrast - ✔✔differences in intensity between two objects or an object and it's
background
✔✔The total magnification using a 10 ocular and a 100 objective would be - ✔✔1000
✔✔Dark field - ✔✔a bright specimen
✔✔Bright field - ✔✔colored or clear specimen
✔✔Phase-contrast - ✔✔specimen has light and dark areas
✔✔What part of the microscope do you change if you want to have less light entering
the condenser? - ✔✔diaphragm
✔✔What is the primary purpose to use a stain in microscopy? - ✔✔To enhance contrast
✔✔Why do you have to heat fix the smear on the slide when performing staining
techniques? - ✔✔kills bacteria, allows easy staining, firmly adheres the smear
✔✔Why are most bacterial stains basic stains? - ✔✔Because they only need to
determine size, shape, and arrangement of cells
✔✔Gram Stain Procedure - ✔✔
✔✔Why does the Gram stain not work well for Mycobacterium - ✔✔It has large amounts
of waxy lipids in their cell walls so they do not readily stain with the water-soluble dyes
✔✔Which stain would you use for Mycobacterium? - ✔✔Acid fast stain
✔✔What stain uses carbolfuchsin? - ✔✔Flagellar stain
✔✔A ________ is a substance that binds to a dye and makes it less soluble. -
✔✔mordant
✔✔Name 3 simple stains - ✔✔Crystal violet
Methylene blue
Gram safranin
